Ueno, T.; Watanabe, Y.

J. Am. Chem. Soc. 2008, 130, 10512-10514, 10.1021/ja802463a

We report the preparation of organometallic Pd(allyl) dinuclear complexes in protein cages of apo-Fr by reactions with [Pd(allyl)Cl]2 (allyl = η3-C3H5). One of the dinuclear complexes is converted to a trinuclear complex by replacing a Pd-coordinated His residue to an Ala residue. These results suggest that multinuclear metal complexes with various coordination structures could be prepared by the deletion or introduction of His, Cys, and Glu at appropriate positions on protein surface.

Ueno, T.

Chem. Commun. 2011, 47, 170-172, 10.1039/C0CC02221G

Apo-ferritin (apo-Fr) mutants are used as scaffolds to accommodate palladium (allyl) complexes. Various coordination arrangements of the Pd complexes are achieved by adjusting the positions of cysteine and histidine residues on the interior surface of the apo-Fr cage.

Harada, A.

Inorg. Chem. 1997, 36, 6099-6102, 10.1021/ic9610849

Antibody 03-1, which was prepared by immunization with meso-tetrakis(4-carboxyphenyl)porphyrin (TCPP) conjugate, has been found to bind strongly to Mn(III)−TCPP and Fe(III)−TCPP complexes with dissociation constants of 4.1 × 10-7 and 1.5 × 10-7 M, respectively, although other monoclonal antibodies raised against TCPP did not bind to these TCPP−metal complexes. The complexes of antibody 03-1 with Mn(III)−TCPP and Fe(III)−TCPP were found to catalyze oxidation of pyrogallol selectively. A Lineweaver-Burk plot for the oxidation of pyrogallol by the antibody−Fe−TCPP complex showed Km = 4.0 mM and kcat = 50 min-1. Studies on the effect of the molar ratio of the antibody to metalloporphyrin on the catalytic activity showed that a 1:1 complex was the most effective for the reaction. The effect of salt (NaCl) on the reaction showed that electrostatic interaction between the antibody and the metalloporphyrin was important for the reaction. The antibody−metalloporphyrin complexes are stable enough to show catalytic activity in the presence of an excess amount of H2O2.

Ueno, T.; Watanabe, Y.

J. Am. Chem. Soc. 2009, 131, 6958-6960, 10.1021/ja901234j

Polymerization reactions of phenylacetylene derivatives are promoted by rhodium complexes within the discrete space of apo-ferritin in aqueous media. The catalytic reaction provides polymers with restricted molecular weight and a narrow molecular weight distribution. These results suggest that protein nanocages have potential for use as various reaction spaces through immobilization of metal catalysts on the interior surfaces of the protein cages.